By Associated Press

A wildfire bore down on rural southeastern Montana towns Thursday as continuing hot, dry weather throughout the West drove flames through more than a dozen states.

Several thousand people in Montana remained under evacuation orders as the Richard Spring Fire advanced across the sparsely-populated Northern Cheyenne Indian Reservation.

Meanwhile, California’s Dixie Fire — which started July 13 and is the largest wildfire burning in the nation — threatened a dozen small communities in the northern Sierra Nevada even though its southern end was mostly corralled by fire lines.

The fire has burned over 780 square miles (over 2,000 square kilometers), destroyed some 550 homes and nearly obliterated the town of Greenville last week. It was 30% contained.

Primed by heavy, swirling winds and hot temperatures, the Montana fire spread in multiple directions, torching trees and sending off embers that propelled the flames across the dry landscape.

It had grown by tens of thousands of acres Wednesday, according to the National Interagency Fire Center. The blaze, which was only 15% surrounded, began Sunday and winds gusting up to 59 miles per hour (95 kilometres per hour) caused it to explode across more than 230 square miles (600 square kilometers).

The fire had crept within about 2 miles (3.2 kilometers) of the eastern edge of the evacuated town of Lame Deer, leaping over a highway where officials had hoped to stop it.

After a second fire ignited just west of the town and quickly spread, tribal officials late Wednesday urged residents who did not heed the initial evacuation order to flee. Busses were being brought in to move people to a school in the community of Busby, about 15 miles (24 kilometers) away.

Firefighters worked into early Thursday morning on hills around Lame Deer to keep the blaze from destroying houses, officials said.

There were no immediate damage reports about buildings.

Rancher Jimmy Peppers sat on his horse east of town, watching an orange glow grow near the site of his house as the night wore on.

“I didn’t think it would cross the highway so I didn’t even move my farm equipment,” said Peppers, who spent the afternoon herding his cattle onto a neighbor’s pasture closer to town. “I don’t know if I’ll have a house in the morning.”

The town of about 2,000 people is home to the tribal headquarters and several subdivisions and is surrounded by steep, rugged, forest.

A few miles from town, Krystal Two Bulls and some friends stuck around to clear brush from her yard in hopes of protecting it from the flames. Thick plumes of smoke rose from behind a tree-covered ridgeline just above the house.

“We’re packed and we’re loaded so if we have to go, we will,” Two Bull said. “I’m not fearful; I’m prepared. Here you don’t just run from fire or abandon your house.”

Also ordered to leave were about 600 people in and around Ashland, a small town just outside the reservation. Local, state and federal firefighters were joined by ranchers using their own heavy equipment to carve out fire lines around houses.

Cooler weather and less wind was in the weather forecast for southeastern Montana Thursday, the National Weather Service said. That could give firefighters brief relief before a ridge of high pressure moves into the area and pumps temperatures into the 90s over the weekend.

Extreme drought conditions have left trees, grass and brush bone-dry throughout many Western states, leaving them ripe for ignition. Montana alone had 25 large wildfires burning, according to the National Interagency Fire Center.

At the same time, California and some other states were facing flows of monsoonal moisture that were too high to bring real rain but could create thunderstorms that bring new fire risks of dry lightning and erratic winds.

In Northern California, a number of wildfires and the threat of more prompted three national forests to close down the Trinity Alps Wilderness Area, a 780-square mile (2,000-square kilomter) area of granite peaks, lakes and trails, into November.

“Tracking hikers in unsafe areas pulls much-needed aircraft away from firefighting efforts, and adds risk and exposure to first responders. Additionally, forest managers hope to limit the possibility of human-caused fires with this temporary full closure,” Shasta-Trinity National Forest officials said in a statement.

Scientists have said climate change has made the region much warmer and drier in the past 30 years and will continue to make the weather more extreme and wildfires more frequent and destructive. The more than 100 large wildfires in the American West come as parts of Europe are also burning.